Published 4:00 am, Wednesday, January 16, 2002

2002-01-16 04:00:00 PDT Washington -- The Supreme Court reaffirmed yesterday that police have broad leeway in deciding when to pull over vehicles and that they may rely on innocent-looking actions as grounds for their suspicions.

Even slowing down at the sight of a parked squad car or driving a minivan can be factors in some cases that weigh in favor of stopping a motorist, the justices said.

The unanimous ruling revived marijuana-smuggling charges against an Arizona man whose slow-moving minivan was stopped by a Border Patrol agent near the Mexican border.

More significantly, the Supreme Court used the case to reiterate that there is no "neat set of legal rules" to say when officers have the required "reasonable suspicion" to stop a motorist.

It is more than "a mere hunch," but well less than actual evidence of wrongdoing, said Chief Justice William Rehnquist. Officers can rely on a "common-sense inference" from what they observe to decide when a vehicle should be pulled over. And judges should not casually second-guess these decisions, Rehnquist added.

Rehnquist and Reinhardt differ on their interpretations of the Fourth Amendment, which forbids "unreasonable searches and seizures" by the government.

Rehnquist has insisted that judges should not tie the hands of police officers. Reinhardt has argued that judges should protect the privacy of pedestrians and motorists by limiting the police from conducting searches without warrants.

They clashed over a case that began on a January afternoon in 1998 in southern Arizona. Agent Clinton Stoddard noticed a minivan traveling on a dirt road north of Douglas, Ariz. Smugglers frequently take these back roads to avoid checkpoints on the highways.

When the minivan approached him, it slowed sharply and the driver sat rigid,

avoiding eye contact. In the back seat were children whose knees were visible,

as if they were resting on something large.

When the minivan suddenly turned onto another remote road, the last turn before a checkpoint, the agent decided to stop the vehicle. After questioning the driver, Ralph Arvizu, the agent learned that he lived in a neighborhood known for smuggling and drug-dealing. He then searched the minivan and found a duffel bag with 128 pounds of marijuana.

When Arvizu appealed his case, the appellate court ruled that it was an "illegal stop" because the agent had relied on too many innocent actions as grounds for stopping the motorist.

Civil libertarians have faulted the high court for giving police unchecked authority to stop vehicles. This can lead to "racial profiling" against minority motorists, and it can result in annoying and unwarranted stops, they say. One brief filed with the court noted that a study by the American Civil Liberties Union had found that of 34,000 highway stops by the California Highway Patrol in 1997, only 2 percent resulted in arrests.

But the Supreme Court took up the government's appeal in U.S. vs. Arvizu and reversed the 9th Circuit.

The chief justice said searches should be judged by "the totality of the circumstances," and here, a variety of factors tip the balance in favor of stopping Arvizu. He was driving along a dirt road on a route used by smugglers and taking actions that seemed intended to avoid the police.

"Undoubtedly, each of these factors alone is susceptible to innocent explanation," Rehnquist said. "Taken together, we believe they sufficed to form a particularized and objective basis for Stoddard's stopping the vehicle."